STN-SR in SRVCC
STN-SR (Session Transfer Number for SRVCC), is a temporary directory number that uniquely identifies the user's active voice call during the SRVCC handover.
The HSS (Home Subscriber Server), or the MME (Mobility Management Entity) in the 4G/LTE network can allocate this number. And then they send this number to the UE and the target 2G/3G network during the SRVCC handover preparation process.
So that the STN-SR number ensures that the active voice call can seamlessly transfer from the 4G/LTE network to the 2G/3G circuit-switched network. Which provides call continuity for the user.
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VoLTE (Voice over LTE) Introduction
While the UE attached to LTE network, the UE can initiate, or receive a voice or a video call. The UE achieves this, by connecting to an external network, which is the 'IMS' network. We can call this, Voice over LTE (VoLTE). This is exactly like when you would like to create a call, while…
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What is an ‘EPS Bearer’ in LTE ?
During 'LTE attach' procedure, the network establishes this EPS Bearer between the UE and the PGW. The PGW assigns an IP address for this Bearer. The UE uses this IP address, in order to communicate with the PDN. In addition, the PGW assigns a QoS for this Bearer, which guarantees the QoS for the data…
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LTE (4G) Network Architecture
LTE (4G) Network Nodes LTE refers to 'Long Term Evolution', and the architecture of the LTE (4G) network is as following, eNodeB The eNodeB is the 4G site that the UE connects to. It provides the radio interface to the UE. MME MME refers to 'Mobility Management Entity'. The MME is responsible for authenticating the…
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